This project has two areas of concern: The first is the quantitative measurement of changes in the conformation of the skull and jaws (bone remodeling), and of alteration in the thickness and contour of the pharyngeal and facial soft tissues associated with certain types of orthodontic treatment. The design of the study is empirical and naturalistic. Independent samples of treated cases are selected retrospectively from the clinical practices of expert clinicians, each of whom has employed the extra-oral or intra-oral treatment technique of his choice to restrain the forward development of the maxilla. The second area is the development of special computer-aided methods for use in craniofacial research. These methods include techniques for rapid and precise data reduction from lateral skull radiograms and for the efficient conduct of hypothesis testing experiments upon large merged data bases of stored craniofacial measurements of different types. The methods and technology developed in the second area will be used in the analysis of the data acquired in the first area.